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(3 pts) Suppose you have two flowering plants of the same species: one has red-c

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Question

(3 pts) Suppose you have two flowering plants of the same species: one has red-colored flowers, the other has white flowers. Both plants are pure-breeding for this trait of flower color. You perform a cross between these plants and all the F, offspring have red flowers. You then mate the F plants and obtain 142 red-flowered plants, 48 purple-flowered plants and 63 white-flowered plants A. (1 pt) What pattern of inheritance best describes how flower color is transmitted in these plants? What phenotypic ratio is expected for this pattern of inheritance. Justify your answer, what phenotypic characteristic(s) of inheritance led you to this conclusion (and it is NOT Incomplete Dominance)? Why can't it be incomplete dominance? B. (2 pts) Use Chi-square analysis to test this hypothesis. Do you accept or reject the hypothesis? YOU MUST SHOW ALL YOUR WORK, INTERPRETATION AND SUPPORT FOR YOUR CONCLUSION

Explanation / Answer

A) given number of offspring of F1 plants is 142 red-flowered plants, 48 purple-flowered plants and 63 white- flowered plants.

lets find the ratio by dividing the lowest number of given data which is 48

142/48 : 48/48 : 63/48

2.95 : 1 : 1.3 ....... multiply this by 3 we will find 8.85 : 3 : 3.9 which is very much near to ratio 9 : 3 : 4. Therefore, it signify that it has recessive epistasis pattern. Phenotypic ratio is expected to be 9 : 3 : 4.

if it were the case of incomplete dominance then ratio would have nearly 1:2:1.

B)

O

E

E-O

(E-O)2

(E-O)2 / E

142

139.5

-2.5

6.25

0.044802867

43

46.5

3.5

12.25

0.26344086

63

62

-1

1

0.016129032

2 = (E-O)2 / E

from table putting the value of (E-O)2 / E in above equation we get

  2 = 0.324

now total number of trait in given problem is n= 3 (red, purple and white)

so degree of freedom = n-1 = 2

comparing the chi square value togather with df( degree of freedom) in chi square distribution table

the probability of hypothesis to be correct is nearly 0.9 which is nearly 90%. Therefore, I will accept the hypothesis that the inheritance pattern follow recessive epistasis.

O

E

E-O

(E-O)2

(E-O)2 / E

142

139.5

-2.5

6.25

0.044802867

43

46.5

3.5

12.25

0.26344086

63

62

-1

1

0.016129032